Sterling Dehumidifier SDA AP-1 User manual

SDA Large AP-1 Control

Dehumidifying Dryer

Part Number: 882.00295.00

Bulletin Number: DH1-615-1

Effective: 04/28/2008

Write Down Your Serial Numbers Here For Future Reference:

_________________________ _________________________

We are committed to a continuing program of product improvement.

Specifications, appearance, and dimensions described in this manual are subject to change without notice.

DCN No. ____________

Large Dehumidifying Dryers ii

Shipping Info

Unpacking and Inspection

You should inspect the large dehumidifying dryer for possible shipping damage.

Thoroughly check the equipment for any damage that might have occurred in transit, such as

broken or loose wiring and components, loose hardware and mounting screws, etc.

In the Event of Shipping Damage

According to the contract terms and conditions of the Carrier, the responsibility of the

Shipper ends at the time and place of shipment.

Notify the transportation company’s local agent if you discover damage.

Hold the damaged goods and packing material for the examining agent’s inspection. Do not

return any goods before the transportation company’s inspection and authorization.

File a claim with the transportation company. Substantiate the claim by referring to the

agent’s report. A certified copy of our invoice is available upon request. The original Bill of

Lading is attached to our original invoice. If the shipment was prepaid, write us for a

receipted transportation bill.

Advise customer service regarding your wish for assistance and to obtain an RMA (return

material authorization) number.

If the Shipment is Not Complete

Check the packing list as back-ordered items are noted on the packing list. You should have:

; Large Dehumidifying Dryer

; Bill of lading

; Packing list

; Operating and Installation packet

; Electrical schematic and panel layout drawings

; Component instruction manuals

Re-inspect the container and packing material to see if you missed any smaller items during

unpacking.

If the Shipment is Not Correct

If the shipment is not what you ordered, contact the parts and service department

immediately at [262] 641-8610. Have the item and order numbers ready. Hold the items

until you receive shipping instructions.

Large Dehumidifying Dryers iii

Returns

Do not return any damaged or incorrect items until you receive shipping instructions from the

shipping department.

Large Dehumidifying Dryers iv

Table of Contents

CHAPTER 1: SAFETY................................................................7

1-1 How to Use This Manual.............................................................................................7

Safety Symbols Used in this Manual.....................................................................7

1-2 Warnings and Precautions..........................................................................................8

1-3 Responsibility..............................................................................................................9

General Responsibility...........................................................................................9

Operator Responsibility.........................................................................................9

Maintenance Responsibility.................................................................................10

Reporting a Safety Defect ...................................................................................11

CHAPTER 2: FUNCTIONAL DESCRIPTION...........................12

2-1 Models Covered in This Manual................................................................................12

2-2 General Description...................................................................................................12

Specifying a Drying System ................................................................................12

What is Desiccant?..............................................................................................12

The Closed Loop Drying System.........................................................................12

The Process/Regeneration Cycle........................................................................13

Sequence of Operation .......................................................................................13

2-3 Standard Features.....................................................................................................14

Auto Start Timer ..................................................................................................14

Mechanical Features...........................................................................................14

Electrical Features...............................................................................................14

2-4 Options......................................................................................................................15

Dewpoint Extend .................................................................................................15

Closed-Loop Regeneration .................................................................................15

2-5 Drawings and Diagrams............................................................................................16

Process Aftercooler.............................................................................................18

Aftercooler Design Specifications........................................................................18

Process Air Dust Collector...................................................................................18

Material Overdrying Protection............................................................................20

Mechanical Options.............................................................................................21

Electrical Options ................................................................................................21

Controller Options ...............................................................................................21

2-6 Safety Devices and Interlocks...................................................................................22

Dimensions and Specifications

9

Denotes availability..................................24

Mechanical Options

9

Denotes availability..................................................24

Electrical Features...............................................................................................25

Electrical Options ................................................................................................25

CHAPTER 3: MECHANICAL INSTALLATION ........................26

3-1 Uncrating the Equipment...........................................................................................26

3-2 Rigging and Placing Unit...........................................................................................26

3-3 Making Electrical Connections..................................................................................26

3-4 Making Gas Line Connections (Gas-Fired Models Only)..........................................27

3-5 Checking for Proper Blower Rotation........................................................................28

3-6 Making Dryer/Drying Hopper Process Air Connections ............................................29

Large Dehumidifying Dryers v

3-7

Connecting Aftercooler/Precooler Cooling Water (Optional).....................................32

3-8 Using the Drying Hopper Air Trap.............................................................................33

CHAPTER 4: CONTROLS........................................................34

4-1 Controller Description................................................................................................34

4-2 Identifying Control Panel Components for the AP-1 Optional Controller................35

Disconnect Switch...............................................................................................35

Control Power Switch..........................................................................................35

Touch Screen......................................................................................................35

Alarm Horn & Light..............................................................................................35

4-3 Process Air Temperature and Conveying Process Controller...................................35

...................................................................35

4-4 Identifying Controller Screens...................................................................................36

Main Menu Screen...............................................................................................................36

Typical Dryer Screens..........................................................................................................36

System Screens..................................................................................................43

Alarm Screens.....................................................................................................48

Alarm Screen Example........................................................................................49

See Section 7-4: Alarms on p. 57 for alarm descriptions.............................................................49

4-5 Redundant Safety Controller Display........................................................................49

4-6 Setting the Redundant Safety Controller...................................................................50

CHAPTER 5: OPERATION.......................................................52

5-1 Start-up......................................................................................................................52

5-2 Using the Dryer Status Screen..................................................................................53

5-3 Alarms.......................................................................................................................54

................................................................................54

5-4 Alarm Descriptions....................................................................................................54

5-5 Shutdown ..................................................................................................................55

CHAPTER 6: MAINTENANCE .................................................56

6-1 Maintenance Schedule..............................................................................................56

6-2 Preventative Maintenance.........................................................................................57

Cleaning or Replacing the Process Air Filters.....................................................57

Cleaning or Replacing the Regeneration Filter....................................................58

Calibrating the Dirty Filter Alarm..........................................................................58

Checking the Dewpoint Control System..............................................................59

6-3 Corrective Maintenance ............................................................................................60

Symptoms of Worn Out Desiccant ......................................................................60

Replacing the Desiccant......................................................................................60

Replacing the Process Heater (Electric Dryers)..................................................61

Large Dehumidifying Dryers vi

Replacing the Regeneration Heater (Electric Dryers) .........................................62

CHAPTER 7: TROUBLESHOOTING .......................................64

7-1 Introduction................................................................................................................64

7-2 Basic Troubleshooting...............................................................................................64

7-3 Determining Temperature Controller Errors or Sensor Errors...................................66

Using a Thermocouple........................................................................................66

Using a Platinum Resistance Thermometer........................................................66

CHAPTER 8: APPENDIX..........................................................67

8-1 Returned Material Policy...........................................................................................67

8-2 Technical Specifications............................................................................................68

Annex B Information............................................................................................68

8-3 Spare Parts List.........................................................................................................69

8-4 8-5 Dryer Identification (Serial Number) Tag.............................................................70

8-4 8-5 Dryer Identification (Serial Number) Tag.............................................................71

8-5 Technical Assistance.................................................................................................72

Parts Department ................................................................................................72

Service Department.............................................................................................72

Sales Department................................................................................................72

Contract Department...........................................................................................72

Large Dehumidifying Dryers Safety 7

Chapter 1: Safety

1-1 How to Use This Manual

Use this manual as a guide and reference for installing, operating, and maintaining the large

dehumidifying dryer. The purpose is to assist you in applying efficient, proven techniques

that enhance equipment productivity.

This manual covers only light corrective maintenance. No other maintenance should be

undertaken without first contacting a service engineer.

The Functional Description section outlines models covered, standard features, and safety

features. Additional sections within the manual provide instructions for installation, pre-

operational procedures, operation, preventive maintenance, and corrective maintenance.

The Installation chapter includes required data for receiving, unpacking, inspecting, and setup

of the large dehumidifying dryer. We can also provide the assistance of a factory-trained

technician to help train your operator(s) for a nominal charge. This section includes

instructions, checks, and adjustments that should be followed before commencing with

operation of the dryer. These instructions are intended to supplement standard shop

procedures performed at shift, daily, and weekly intervals.

The Operation chapter includes a description of electrical and mechanical controls, in

addition to information for operating the dryer safely and efficiently.

The Maintenance chapter is intended to serve as a source of detailed assembly and

disassembly instructions for those areas of the equipment requiring service. Preventive

maintenance sections are included to ensure that the dehumidifying dryer provides excellent,

long service.

The Troubleshooting chapter serves as a guide for identification of most common problems.

Potential problems are listed, along with possible causes and related solutions.

The Appendix contains technical specifications, drawings, schematics, parts lists, and

available options. A spare parts list with part numbers specific to your machine is provided

with your shipping paperwork package. Refer to this section for a listing of spare parts for

purchase. Have your serial number and model number ready when ordering.

Safety Symbols Used in this Manual

The following safety alert symbols are used to alert you to potential personal injury hazards.

Obey all safety messages that follow these symbols to avoid possible injury or death.

DANGER! DANGER indicates an imminently hazardous situation that, if not avoided,

will result in death or serious injury.

WARNING! WARNING indicates a potentially hazardous situation or practice that, if

not avoided, could result in death or serious injury.

Caution! CAUTION indicates a potentially hazardous situation or practice that, if

not avoided, may result in minor or moderate injury or in property damage.

Large Dehumidifying Dryers Safety 8

Dryer Safety Tags

Tag Description Tag Description

Read Operation &

Installation Manual

High Voltage Inside

Enclosure

Hot!

Lifting Point

PE

Protected Earth

Ground

Earth Ground

1-2 Warnings and Precautions

Our equipment is designed to provide safe and reliable operation when installed and operated

within design specifications, following national and local safety codes. This may include, but

is not limited to OSHA, NEC, CSA, SPI, and any other local, national and international

regulations.

To avoid possible personal injury or equipment damage when installing, operating, or

maintaining this equipment, use good judgment and follow these safe practices:

; Read and follow these operation and installation instructions when installing,

operating, and maintaining this equipment. If these instructions become

damaged or unreadable, additional copies are available from the manufacturer.

; Follow all SAFETY CODES.

; Wear SAFETY GLASSES and WORK GLOVES.

; Work only with approved tools and devices.

; Disconnect and/or lock out power before servicing or maintaining the equipment.

; Use care when LOADING, UNLOADING, RIGGING, or MOVING this

equipment.

; Operate this equipment within design specifications.

; OPEN, TAG, and LOCK ALL DISCONNECTS before working on equipment.

You should remove the fuses and carry them with you.

; Make sure the equipment and components are properly GROUNDED before you

switch on power.

; When welding or brazing in or around this equipment, make sure VENTILATION is

ADEQUATE. PROTECT adjacent materials from flame or sparks by shielding with

sheet metal. An approved FIRE EXTINGUISHER should be nearby and ready for

use if needed.

; Do not restore power until you remove all tools, test equipment, etc., and the

equipment and related components are fully reassembled.

Large Dehumidifying Dryers Safety 9

; Only PROPERLY TRAINED personnel familiar with the information in this

manual should work on this equipment.

We have long recognized the importance of safety and have designed and manufactured our

equipment with operator safety as a prime consideration. We expect you, as a user, to abide

by the foregoing recommendations in order to make operator safety a reality.

1-3 Responsibility

These machines are constructed for maximum operator safety when used under standard

operating conditions and when recommended instructions are followed in the maintenance

and operation of the machine.

All personnel engaged in the use of the machines should become familiar with their operation

as described in this manual.

Proper operation of the machine promotes safety for the operator and all workers in its

vicinity.

Each individual must take responsibility for observing the prescribed safety rules as outlined.

All warning and danger signs must be observed and obeyed. All actual or potential danger

areas must be reported to your immediate supervisor.

General Responsibility

No matter who you are, safety is important. Owners, operators and maintenance personnel

must realize that every day, safety is a vital part of their jobs.

If your main concern is loss of productivity, remember that production is always affected in a

negative way following an accident. The following are some of the ways that accidents can

affect your production:

• Loss of a skilled operator (temporarily or permanently)

• Breakdown of shop morale

• Costly damage to equipment

• Downtime

An effective safety program is responsible and economically sound.

Organize a safety committee or group, and hold regular meetings. Promote this group from

the management level. Through this group, the safety program can be continually reviewed,

maintained, and improved. Keep minutes or a record of the meetings.

Hold daily equipment inspections in addition to regular maintenance checks. You will keep

your equipment safe for production and exhibit your commitment to safety.

Please read and use this manual as a guide to equipment safety. This manual contains safety

warnings throughout, specific to each function and point of operation.

Operator Responsibility

The operator’s responsibility does not end with efficient production. The operator usually has

the most daily contact with the equipment and intimately knows its capabilities and

limitations.

Plant and personnel safety is sometimes forgotten in the desire to meet incentive rates, or

through a casual attitude toward machinery formed over a period of months or years. Your

Large Dehumidifying Dryers Safety 10

employer probably has established a set of safety rules in your workplace. Those rules, this

manual, or any other safety information will not keep you from being injured while operating

your equipment.

Learn and always use safe operation. Cooperate with co-workers to promote safe practices.

Immediately report any potentially dangerous situation to your supervisor.

; NEVER place your hands or any part of your body in any dangerous location.

; NEVER operate, service, or adjust the dryer without appropriate training and first

reading and understanding this manual.

; NEVER try to pull material out of the dryer with your hands while it is running!

; Before you start the dehumidifying dryer, check the following:

• Remove all tools from the dryer;

• Be sure no objects (tools, nuts, bolts, clamps, bars) are laying in the

area;

; If your dryer has been inoperative or unattended, check all settings before starting.

; At the beginning of your shift and after breaks, verify that the controls and other

auxiliary equipment are functioning properly.

; Keep all safety guards in place and in good repair. NEVER attempt to bypass, modify,

or remove safety guards. Such alteration is not only unsafe, but will void the

warranty on your equipment.

; When changing control settings to perform a different mode of operation, be sure

selector switches are correctly positioned. Locking selector switches should only be

adjusted by authorized personnel and the keys removed after setting.

; Report the following occurrences IMMEDIATELY:

• unsafe operation or condition

• unusual dryer action

• leakage

• improper maintenance

• NEVER stand or sit where you could slip or stumble into the

dehumidifying dryer while working on it.

; DO NOT wear loose clothing or jewelry, which can be caught while working on the

dryer. In addition, cover or tie back long hair.

; Clean the dehumidifying dryer and surrounding area DAILY, and inspect the machine

for loose, missing or broken parts.

; Shut off power to the dryer when it is not in use. Turn the switch to the OFF position,

or unplug it from the power source.

Maintenance Responsibility

Proper maintenance is essential to safety. If you are a maintenance worker, you must make

safety a priority to effectively repair and maintain equipment.

Before removing, adjusting, or replacing parts on a machine, remember to turn off all electric

supplies and all accessory equipment at the machine, and disconnect and lockout electrical

and pneumatic power. Attach warning tags to the disconnect switch and air shutoff valve.

Large Dehumidifying Dryers Safety 11

When you need to perform maintenance or repair work on a dehumidifying dryer above floor

level, use a solid platform or a hydraulic elevator. If there is a permanently installed catwalk

on your dryer, use it. The work platform should have secure footing and a place for tools and

parts. DO NOT climb on the dehumidifying dryer, machines, or work from ladders.

If you need to repair a large component, use appropriate handling equipment. Before you use

handling equipment (portable “A” frames, electric boom trucks, fork trucks, overhead cranes)

be sure the load does not exceed the capacity of the handling equipment or cause it to become

unstable.

Carefully test the condition of lifting cables, chains, ropes, slings, and hooks before using

them to lift a load.

Be sure that all non-current carrying parts are correctly connected to earth ground with an

electrical conductor that complies with current codes. Install in accordance with national and

local codes.

When you have completed the repair or maintenance procedure, check your work and remove

your tools, rigging, and handling equipment.

Do not restore power to the dehumidifying dryer until all persons are clear of the area. DO

NOT start and run the dryer until you are sure all parts are functioning correctly.

BEFORE you turn the dehumidifying dryer over to the operator for production, verify all

enclosure panels, guards and safety devices are in place and functioning properly.

Reporting a Safety Defect

If you believe that your equipment has a defect that could cause injury, you should

immediately discontinue its use and inform the manufacturer.

The principle factors that can result in injury are failure to follow proper operating procedures

(i.e. lockout/tagout), or failure to maintain a clean and safe working environment.

Large Dehumidifying Dryers Functional Description 12

Chapter 2: Functional Description

2-1 Models Covered in This Manual

This manual provides operation, installation, and maintenance instructions for 600-3000 cfm

Large Dehumidifying Dryers with AP1 control. These dryers are available with electric

heaters or gas burners. Gas dryers are indicated with a “G” in the model number. Model

numbers are listed on the serial tag. Make sure you know the model and serial number of

your equipment before contacting the manufacturer for parts or service.

Our dehumidifying dryers are designed to generate heated, dehumidified air at carefully

controlled temperatures for use in closed-loop plastic drying systems. Dehumidifying dryers

are sized to meet the specific requirements stated by the Customer at the time of purchase.

2-2 General Description

Moisture removal from hygroscopic (moisture attracting) plastic pellets is an essential step in

the manufacture of high-quality plastic products.

Our Dehumidifying Dryers are used by the plastics industry to generate very low dewpoint

air that is heated to a controlled temperature for drying plastic pellets and regrind.

The drying system consists of a dry air source and drying hoppers with process heating

controls. The dry air source controls two primary sub-systems, the process air and the

regeneration circuit. Each dryer has a left and a right desiccant bed so that one bed can

regenerate while the other is in use. 2000-3000 cfm dryers feature two sets of desiccant beds,

for a total of four desiccant beds.

The drying system can be configured for one drying hopper or for as many as 20 hoppers.

The process air heater can be located on the dryer or on each individual drying hopper.

Heaters that are located on the drying hoppers can be set up with their own independent

controls or can be controlled centrally using the main dryer controller.

Specifying a Drying System

There were many variables considered in the selection of your drying system, including: type

of materials, residence time, throughput of the extruder or injection molding machine,

ambient air moisture and temperature, and the altitude at the processing site. Should your

operating environment change, we can advise you on necessary equipment, process time and

temperature modifications.

What is Desiccant?

Desiccant is a material that attracts and holds (absorbs) water from the air. The desiccant our

dryers use is a synthetic crystalline metal aluminosilicate that is blended with a clay binder

and formed into beads.

Absorbed water is driven from saturated desiccant by heating it to a high temperature

(reducing the desiccant's capacity to hold water) and forcing air through it. This moisture

removal process is called "regeneration".

The Closed Loop Drying System

These dehumidifying dryers force hot, dry air through the resin in the drying hopper, where

the air picks up moisture from the material and is drawn back to the dryer. In the dryer,

Large Dehumidifying Dryers Functional Description 13

moisture is stripped from the air by a desiccant bed. The dried process air is then re-heated

and delivered back into the drying hopper to dry material again.

This system is a "closed loop", because ambient (outside) air is never introduced into the

process air. The closed loop system is used by the manufacturer because the process air is

typically much drier than ambient air, even after carrying moisture out of the plastic resin.

Recycling process air maintains drying efficiency at a consistently high level.

The Process/Regeneration Cycle

There are two desiccant beds in a dryer up to 1500 cfm. Larger dryers have four beds (two

left and two right beds). While one desiccant bed is on-line in the process air loop, the other

is off-line being regenerated (see Figure 1).

When a desiccant bed is on-line, it absorbs moisture from the process air. The desiccant will

become saturated with moisture and need to be regenerated. The dryer automatically redirects

the process airflow to the second bed and starts regenerating the first bed.

During regeneration, air is heated to approximately 550°F and forced through the saturated

desiccant. The moisture driven off the desiccant is bled to the atmosphere. The regeneration

heater is then turned off while the regeneration blower continues to blow air through the

desiccant bed until it is cooled.

Figure 1: Regeneration Cycle

Regeneration

Filter

Regeneration

Blower

Process

Blower

Regeneration

Exhaust

Process

Heater

Process

Filter

Insulated

Drying

Hopper

Right Desiccant

Regeneration

Heaters

Dryer Valve

Left Desiccant

AD600-AD1500

Dryer Flow Schematic

Right Desiccant in

Regeneration

Filter

Regeneration

Blower

Process

Blower

Regeneration

Exhaust

Process

Heater

Process

Filter

Insulated

Drying

Hopper

Right Desiccant

Regeneration

Heaters

Dryer Valve

Left Desiccant

AD600-AD1500

Dryer Flow Schematic

Left Desiccant in

Regeneration

Sequence of Operation

When the dryer is started, the main air valve rotates 360º and then moves to place the last

successfully regenerated desiccant bed online. If the dryer was powered off using the main

power disconnect or E-stopped, then the regenerating bed is placed back into regeneration,

and the regeneration cycle is started over. The main air valve is allowed a period of time to

move from one position to the other. If the main air valve does not complete positioning

within the allotted time, then a “Main Air Valve Fail” alarm is generated and the dryer stops

the process air blower and disables the drying hoppers and regeneration circuit.

If the closed loop regeneration option is enabled, the regeneration closed loop valve moves to

the open loop position. The system always begins the cooling phase for a regeneration cycle

using ambient (open loop) air. The closed loop regeneration valve is allowed a period of time

to move from the closed to the open loop position and a “Closed Loop Valve” alarm is

generated if the valve fails to reach the commanded position within this time. This alarm will

disable the regeneration circuit but does not stop the process air system or drying hoppers.

Large Dehumidifying Dryers Functional Description 14

Once the main air valve and closed loop regeneration valve are in place, the process air

blower starts. The system monitors the process air blower’s overload, starter auxiliary contact

feedback and air pressure. Loss of any of these items when the process air blower is running

will cause the process air blower and the drying hopper’s process heaters to shut down.

The process air heaters (or gas burners, on gas-fired dryers) will turn on after a delay to allow

the process air blower to accelerate the operating speed.

During normal operation, one set of desiccant beds is connected to the process air circuit

while the other set is being regenerated. When the offline beds are done regenerating, they

will be switched into the process air circuit and the other beds will be regenerated. The

default bed switch setting is based on time. If the Dewpoint Switch option is enabled, the

beds will switch when the process air dewpoint reaches the dewpoint switch point. The

dewpoint option will automatically disable itself and an alarm will be generated if the

dewpoint sensor or related electronics fail.

2-3 Standard Features

Auto Start Timer

The autostart timer is used to automatically start and stop the dryer at the time you specify. It

can be programmed for one start and/or stop event per day for a week. When the Auto Start

Timer is enabled, the dryer will automatically start and stop at pre-programmed times. If the

dryer is stopped due to the Auto Start Timer, the DRYER STATUS message will indicate

that the Auto Start timer is active.

Mechanical Features

; 180ºF – 250ºF Drying temperature range

; High regeneration temperature control safeties

; 13X desiccant (molecular sieve)

; Easy to access process, regeneration, and combustion air filters.

; High pressure centrifugal blower

; Dew point +15º F to –40º F

Electrical Features

; Electrically-actuated air valve

; NFPA79, UL & CUL machinery electrical standards (Electric Dryers) includes:

• NEMA 12 controls, components & enclosure

• Non-fused electrical disconnect

• Solid state relays for heater control

• Branch fusing

• Lockable power disconnects

• Regeneration temperature control

• “Process high temp” indication light and audible alarm

• 7 day timer

Large Dehumidifying Dryers Functional Description 15

• Sequence shutdown switch

; NFPA86, UL, AGA & CGA machinery electrical standards (Gas Dryers)

; Available supply voltages of 208, 230, 460, 575/3/60 and 400/3/60

2-4 Options

Dewpoint Extend

The Dewpoint Extend option measures the temperature of the moist air as it is bled to the

atmosphere after regeneration. After a period of time, the bleed temperature will rise. This

condition, called "bed breakthrough" indicates that the bed is dry. At bed breakthrough, the

bleed air temperature peaks between 350°F and 400°F.

The regeneration heaters turn off automatically on bed breakthrough for additional energy

savings. A 550°F regeneration temperature will dry the desiccant beds sufficiently to produce

process air dewpoint of -40°F. In a properly sized system, this ultra-low humidity level will

be more than adequate to dry plastics to as little as .003% moisture.

Closed-Loop Regeneration

An optional regeneration closed-loop valve and heat exchanger can be used to close the

regeneration loop during the cooling portion of the regeneration cycle. If this option is

enabled on the dryer, air will be bled to the atmosphere until the heating portion of the

regeneration cycle is finished. Then, the regeneration closed loop valve will direct air through

a water-cooled heat exchanger and back into the regeneration loop (see Figure 2).

Figure 2: Closed Loop Regeneration

AD600-AD1500

Dryer Flow Schematic

Regeneration Closed Loop

Cooling is Activated

Regeneration

Filter

Optional

Regeneration

Closed Loop

Cooler

Regeneration

Blower

Optional

Regeneration

Closed Loop

Valve

Regenerarion

Exhaust

Left Desiccant

Regeneration

Heaters

Dryer Valve

AD600-AD1500

Dryer Flow Schematic

Regeneration Heating is

Activated

Regeneration

Filter

Optional

Regeneration

Closed Loop

Cooler

Regeneration

Blower

Optional

Regeneration

Closed Loop

Valve

Regeneration

Exhaust

Left Desiccant

Regeneration

Heaters

Dryer Valve

Large Dehumidifying Dryers Functional Description 16

2-5 Drawings and Diagrams

Regen.

Filter

Regeneration

Blower

Process

Blower

Optional

After-cooler

Process

Air Filter

Insulated

Drying

Hopper

Left Desiccants

Right Desiccants

Process

Heater

Optional

Regeneration

Closed Loop

Cooler

Optional

Regeneration

Closed Loop

Valve

Regen.

Exhaust

Dryer Valve

Airflow Schematic: 2000-3000 cfm dryers (4 desiccant beds). Left desiccant beds are

regenerating—closed loop regeneration is activated.

Regen.

Filter

Regeneration

Blower

Process

Blower

Optional

After-cooler

Process

Air Filter

Insulated

Drying

Hopper

Left Desiccants

Right Desiccants

Process

Heater

Optional

Regeneration

Closed Loop

Cooler

Optional

Regeneration

Closed Loop

Valve

Regen.

Exhaust

Dryer Valve

Airflow Schematic: 2000-3000 cfm dryers (4 desiccant bed). Left desiccant beds are

regenerating in open-loop regeneration mode.

Large Dehumidifying Dryers Functional Description 17

PS

Differential

Pressure

Switch

Filter Check

Gage

E

F

Dust Level

Indicator

Slide Gate

Clamp

Dust Pan

Filter Retainer

Dust Shroud

Cartridge Filter

Thumb Screws

Optional dryer dust collector

Large Dehumidifying Dryers Functional Description 18

Process Aftercooler

The optional aftercooler cools the moist air returning to the dryer from the drying hopper.

The aftercooler can cool the return air from 250ºF to about 150ºF. This maintains the dryer’s

efficiency and condenses the unwanted plasticizer from the air stream. The aftercooler

requires a cooling water connection (see Figure and page 25).

Figure 3: Process Aftercooler

High

Temperature

Gasket

Cooling Coil

Pipe Gasket

Mounting

Brackets

Stainless Steel

Cooler Housing

Cooling Coil

Cover Plate

High

Temperature

Gasket

Stainless Steel Cooler

Housing

Cooling Coil

Pipe Gasket

Cooling Coil

Cover Plate

Mounting Brackets

Aftercooler Design Specifications

Entering water temp.

ºF ºC

85ºF 29ºC

Process Air Dust Collector

The optional process air dust collector consists of a filter, dust can, pressure gauge, and

optional pressure switch (see Figure). The gauge will let you know whether it is time to clean

out your filters. The optional dirty filter alarm will be activated if the filter is dirty.

Large Dehumidifying Dryers Functional Description 19

Figure 4: Process Air Dust Collector

PS

Differential

Pressure

Switch

Filter Check

Gage

E

F

Dust Level

Indicator

Slide Gate

Clamp

Dust Pan

Filter Retainer

Dust Shroud

Cartridge Filter

Thumb Screws

Large Dehumidifying Dryers Functional Description 20

Material Overdrying Protection

Material Overdrying Protection is an automatic system used to reduce the chance of over-

drying, and possibly melting, the resin in the drying hopper. Material Overdrying Protection

activates when the return temperature is above a set value, indicating that all the resin in the

hopper is dry.

The control system monitors the return air temperature and automatically changes the process

air setpoint to the SET BACK SETPOINT value when the return air temperature rises above

the set back temperature. The process air setpoint returns to normal when the return air

temperature falls below the SETUP TEMPERATURE value. The target values for

changing the process air setpoint can be adjusted on the Mat Protect screen.

Recommended Temperature Settings

Drying Temperature (ºF) 160 180 200 220 240 260 280 300 320 340 360

Setpoint 120 125 130 135 135 140 150 160 170 180 200

Figure 5: Material Miser/Air Balance Valve

Coupling

Temperature

Probe

Drying

Hopper

Valve

Proofing

Switch

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Sterling Dehumidifier SDA AP-1 User manual

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